JPS57147380A - Video signal generator - Google Patents

Abstract

PURPOSE:To obtain a stable generator which is formed into an IC, by setting the time of a horizontal synchronizing signal after dividing the reference signal and at the same time setting the periods of the white and black signals within the above-mentioned time plus the different levels of these white and black signals to deliver a white/black image. CONSTITUTION:An oscillating circuit 44 produces a clock pulse, i.e., the reference signal in the form of an oscillating element and supplies it to a time setting circuit 46. The outputs of 1/2 dividers 58, 60, etc. are supplied to an AND circuit 70, and the output of the circuit 70 is inverted to obtain the 1st time set output having a horizontal synchronizing signal time tH. The output Q' of a divider 64 is further divided and inverted to obtain the 2nd time set output so the white and black signal periods tPW and PPB each. These outputs are supplied to a circuit 48 which sets different levels, and the output of the circuit 48 is extracted out of a terminal 82 in the form of a video signal. In such a way, a stable test video signal generator which is mounted to a VTR, for example, is obtained with an inexpensive cost to be suited for an IC and with no control and high timing accuracy.